As a technique of this kind, there has hitherto been a sputter type ion source of a so-called hot cathode system, in which a sputter electrode is constituted of a material intended to be ionized and a negative voltage is applied to the sputter electrode to emit sputter particles, and the emitted sputtered particles are ionized through the use of thermoelectrons emitted from a filament (see Patent Document 1, for example). Patent Document 1: Japanese Patent Laid-Open Application No. 2003-306767